1. Field of the Invention
The present invention relates to a liquid crystal panel and a liquid crystal display (LCD), and more specifically to a color-filter-on-array (COA) type liquid crystal panel and an LCD including the COA type liquid crystal panel.
2. Description of the Prior Art
A COA type LCD is an LCD having a color filter (CF) and thin film transistor (TFT) arrays disposed on the same substrate. In addition to an aperture ratio being effectively improved, the COA type LCD further can solve an alignment problem which occurs in a large-sized panel, as well as decreases current leakage being generated from a light exposure; and thus COA technology is applicable to a display of the large-sized panel.
The TFT arrays are used as a driving element. Existing TFT technology mainly uses amorphous silicon (a-Si) and poly-silicon (poly-Si). A Poly-silicon TFT is chiefly characterized by a high electron mobility, a smaller device size, and a large aperture ratio, thereby significantly improving image resolution. However, a low temperature poly-silicon (LTPS) process is quite complex, and is characterized by high manufacturing costs, low yield, and poor uniformity. In comparison with the Poly-silicon TFT, an amorphous silicon TFT is characterized by a low electron mobility, a larger TFT device size, and a smaller aperture ratio of a pixel. However, amorphous silicon manufacturing techniques have made great advances. The amorphous silicon manufacturing techniques are obviously better than poly-silicon manufacturing techniques in terms of manufacturing cost and large-area deposition uniformity.
However, the properties of the amorphous silicon itself result in that it is sensitive to light. Although there are many considerations in design to avoid a TFT being irradiated by a light (e.g., black matrix, bottom gate structure, and the like), the degradation of device characteristics which is caused by photoirradiation may occur unavoidably in practical application (e.g., the degradation of device characteristics which is caused by stray backlights entering into gate electrode circuits of the TFT arrays), thereby affecting the display quality of liquid crystal display.
Therefore, there is a need to provide a liquid crystal panel and a liquid crystal display which can reduce the stray backlights entering into the gate electrode circuits of the TFT arrays, so as to overcome the disadvantage in the prior art.